Method and apparatus for sealing vacuum pack bag



Nov. 9, 1965 METHOD AND APPARATUS FOR SEALING VACUUM PACK BAG OriginalFiled June 11, 1958 T. E. PIAZZE 2 Sheets-Sheet 1 INVENTOR T/zam aazffizazze ATTORNEYS Nov. 9, 1965 T. E. PIAZZE 7 METHOD AND APPARATUS FORSEALING VACUUM PACK BAG Original Filed June 11, 1958 2 Sheets-Sheet 2 INVENTOR ATTORNEYS United States Fatent 3,216,172 METHOD AND APPARATUS FORSEALING VACUUM PACK BAG Thomas E. Piazze, Mount Vernon, Ohio, assignorto Continental Can Company, Inc., New York, N.Y., a corporation of NewYork Original application June 11, 1958, Ser. No. 741,370, now PatentNo. 3,086,693, dated Apr. 23, 1963. Divided and this application Aug.10, 1962, Ser. No. 216,219

3 Claims. (Cl. 53-22) This application is a division of my copendingapplication Serial No. 741,370, filed June 11, 1958, now Patent No.3,086,693 granted April 23, 1963.

In the packaging of cheeses, meats, coffee and various othercommodities, it is quite common to vacuum-pack them in sealed bags ofpolyethylene or other heat-scalable plastic, but difiiculties have beenexperienced in Vacuumizing the filled bags and then tightly sealing themagainst re-entrance of air.

It has been proposed to provide one wall of the bag with anair-evacuating opening for communication with an air evacuating member,to providean internal flexible patch extending over said opening andspaced from said bag wall to form an air-evacuating passagecommunicating with said opening and With the bag interior, and toheatseal said patch to said wall around said opening after evacuation ofair from the bag. However, unless the bag contents so smoothly anduniformly contact with the flexible patch as to prevent distortion ofthis patch during performance of the heat-sealing operation, there isdanger of producing a faulty seal. Also, when vacuum-packaging a ratherfinely granulated or a powdered material, there has been liability ofsome of such material becoming entrained with the outgoing air andbecoming deposited on the opposed surfaces of the bag wall and patchwhich are to be heat-sealed together: and such deposits have interferedwith the production of a perfect seal.

The present invention has aimed to overcome the above mentioneddifiiculties.

In carrying out the above end, a specific object has been to provide animproved patch comprising a relatively stifl? backing sheet and a filmof heat-sealable material secured to the side of said backing sheetwhich faces the bag wall having the air-evacuating opening. Therelatively stifi backing sheet is exposed to the bag contents andtherefore, even if such contents do not contact smoothly and uniformlywith the patch, appreciable patch distortion will be prevented.Consequently, when a heated sealing member is pressed against the bagwall to seal it to the patch film, said bag wall and film will becometightly clamped between the relatively stilf patch backing and saidsealing member, and a perfect seal will be produced.

Another specific object has been to seal all edges of the patch to thebag wall and to admit air to the evacuating passage between the patchand the bag wall, only through perforations in the patch. Thus, byforming these perforations so fine that particles of granulated orpowdered bag contents cannot pass through them, such particles will beexcluded from the opposed surfaces of said patch and bag wall and cannotinterfere with heat sealing.

Further objects have been to provide a novel and advantageous method anda novel and advantageous apparatus for evacuating the air and thensealing the bag against re-entrance of air.

With the above and other objects in view that will hereinafter appear,the nature of the invention will be more clearly understood by referenceto the following detailed description, the appended claims and theseveral views illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a side elevation, partly broken away, showing a bag having aperforated patch, the bag being filled with granular material and inreadiness for the evacuation of air through the perforations in thepatch.

FIGURE 2 is a vertical sectional view, partly in elevation, showing thefilled bag engaged with the air-evacuating and heat-sealing apparatus,the evacuation of air being indicated by arrows.

FIGURE 3 is a view similar to FIGURE 2 but showing the heated sealingring of the apparatus in the act of sealing together the portions of thebag walls and patch around the air-evacuating opening and between thisopening and the patch perforations.

FIGURE 4 is a fragmentary top view showing the bag support, theair-evacuating member and the heat-sealing ring.

FIGURE 5 is a view similar to FIGURE 1 but showing a construction Whichmay be employed when there is no danger of any particles of the bagcontents entering between the patch and the bag wall.

The bag 10 shown in the drawings is constructed from two sheets 11 and12 of plastic heat-scalable stock, three edges of said sheets beingheat-sealed together at the factory, as indicated at 13, leaving the bagopen at one end for filling. The open end is to be heat-sealed at 14,after filling. This type of bag has been shown for illustrative purposesonly and other known bag structures could be employed if desired.

The sheet 11 forms one side wall of the bag and is formed with anair-evacuating opening 15. Within the bag is a patch 16 which extendsacross the opening 15 and is secured to the bag wall 11. Provision ismade for spacing the patch 16 from the wall 11 to provide anairevacuating passage 17 between them, said passage being incommuniaction with the opening 15 and with the bag interior.

In each form of the invention, the patch 16 is of composite form andcomprises a relatively stilt backing sheet 18 and a film 19 secured tothe side of the backing sheet 18 which faces the bag wall 11. Therelatively stiff backing sheet 18 may be formed from cardboard or otherappropriate material having required stiffness to prevent patchdistortion during sealing around the opening 15. The film 19 is ofheat-scalable material, for example polyethylene, and it may be cementedto or otherwise united with the relatively stiff backing sheet 18, or itmay be formed by a layer of heat-scalable cement applied to said backingsheet. In either instance, the film 19 preferably has a multiplicity ofsuitable projections 20 which space the patch 16 from the bag wall 11 toprovide the passage 17. However, this bag wall 11 could well be providedwith equivalent spacing projections, if desired.

In FIGURES 1 to 3, all edges of the patch 16 are heatsealed to the bagwall 11 as indicated at 21 and the passage 17 communicates with the baginterior only through perforations 22. These perforations 22 may be ofany desired shape and they are all radially spaced from the opening 15.While they are shown as disposed in a circular series, this is notessential. All air being evacuated from the bag (see FIGURE 2) flowsthrough the perforations 22 to the passage 17 to and through the opening15. Therefore, by forming the perforations 22 sufiiciently small toprevent granular or powdered bag contents C from passing through them,particles of such contents cannot become deposited on the opposedsurfaces of the patch film 19 and the bag wall 11 and cannot thereforeinterfere with heat sealing of these elements together after airevacuation.

When the bag contents are to be such that there is no danger of anyparticles thereof entering the passage 17, all edges of the compositepatch 16 need not be sealed to the bag wall 11 and said patch need nothave 3 the perforations 22. Such a construction is shown in FIGURE 5 andthe contents are indicated at C. In this view, two edges of the patch 16are shown heat-sealed at 21' to the bag wall 11. The heat sealing 21' isshown in stripe form but could Well be at intervals only.

The apparatus disclosed in FIGURES 2, 3 and 4 is preferably employed ineffecting air evacuation from the bagand in then sealing the latteragainst re-entrance of air. In these views a horizontal table 23 isshown, upon which to lay the filled bag. This table 23 hasan opening 24into which the upper end of an air-evacuating pipe 25 extends, the tableand pipe being fixedly mounted in any suitable way. The upper extremityof the pipe 25 is preferably in the same plane with the top of the table23, is open, and is of a diameter less than that of the table opening 24but greater than that of the bag opening 15. A normally lowered sealingring 26 surrounds the pipe 25 and may be raised by any suitable means.This ring 26 is heated by flame from a burner 27, or in any othersuitable manner, to a temperature at which it may be utilized toheat-seal the bag wall 11 to the patch film 19 after evacuation of airfrom the bag 10.

The filled bag is laid upon the table 23 as seen in FIGURE 2, with itsside wall 11 resting on the upper end of the pipe 25 and with theopening communicating with said pipe. Then by any adequate pump means,partial vacuum is created in the pipe 25. This causes the bag-containedair to enter the passage 17, flow through this passage to the opening 15and flow through this opening to and through the pipe 25. When the patchof FIGURES 1 to 3, is used, the air from the bag enters the passage 17only through the perforations 22. When the patch of FIGURE 5 is employedthe air entersv the passage 17 at the periphery of said patch. When thedesired vacuumizing has been attained, the heated sealing ring 26 israised as seen in FIGURE 3.

19 between the sealing ring 25 and the stilt patch backing 18 and theheat from said sealing ring heat-sealssaid wall 11 and film 19 togetheras seen at 28. As the patch backing 18 prevents distortion of the patchfilm 19, even if the bag contents do not smoothly and uniformly contactwith said backing, a perfect seal is assured. When the patch of FIGURES1 to 3 is employed, the seal 28 is, of course, between the opening 15and the perforations 22. Regardless of which form of patch is used, theprojections in the zone of the seal 28 do not interfere with theformation of said seal, as they become sufficiently fluid to flatten outinto the plane of the film 19.

During the air-evacuating and heat-sealing operations,

a bag hold-down plate 29 may be employed if the weight vantageousprovision has been disclosed for attaining the However, variations mayWell be made desired ends.

This causes tight clamping of the bag wall 11 and thepatch film withinthe scope of the invention as. claimed, audit is.

to be understood that the invention is not restricted to a bag but isadaptable also to other forms of containers, whether flexible throughoutor flexible only at the wall portion which is to be sealed to the patch.

I claim:

1. A method of sealing a flexible heat-scalable wall of a container toan internal heat-scalable patch which extends over an air-evacuatingopening in said wall and provides an air-evacuating passage between saidopening and the interior of said container, the steps of placing saidwall against an air-evacuating member with said air-evacuating openingin communication with said airevacuating member, exhausting air throughsaid opening and said air-evacuating passage and thereby evacuating airfrom the interior of the container, applying a heated sealing memberagainst the outer side of said wall around the air-evacuating memberbefore terminating the evacuation of air from the container, and movingthe heated seal ing member against the wall to press the wall againstsaid patch to seal said wall and patch together and close fluidcommunication between the interior of the container and the openingthrough the air-evacuating passage. I

2. The method defined in claim lincluding the additional step of spacingthe portion of the patch overlying the opening during the evacuation ofthe interior of said container to prevent the patch from beingdrawnagainst portions of the wall adjacent the opening prior to complete evacuation of the container interior whereby com-' having anopening to downwardly expose an area of the bag wall around saidair-evacuating opening, an airevacuating member having an open upper endto abut the exterior of said container wall around said air-evacuatingopening, said upper end of said air-evacuating member being receivedwithin said opening of said table but being spaced from the wall of thisopening, a'sealing ring sur-; rounding said air-evacuating member andraisable into said opening of said table to seal said container wall to"said patch, and means for heating said sealing ring.

References Cited by the Examiner UNITED STATES PATENTS 2,387,812 10/45Sonneborn et al 53112 X 2,708,541 5/55 Jones 53-112 2,778,171 1/57Taunton 53 9. 2,896,385 6/59 Gebhardt 53-112 2,928,216 3/60 vOrsini 53-9X 3,026,656 3/62 FRANK E. BAILEY, Primary Examiner.

Rumsey 5322

1. A METHOD OF SEALING A FLEXIBLE HEAT-SEALABLE WALL OF A CONTAINER TOAN INTERNAL HEAT-SEALABLE PATCH WHICH EXTENDS OVER AN AIR-EVACUATINGOPENING IN SAID WALL AND PROVIDES AN AIR-EVACUATING PASSAGE BETWEEN SAIDOPENING AND THE INTERIOR OF SAID CONTAINER, THE STEPS OF PLACING SAIDWALL AGAINST AN AIR-EVACUATING MEMBER WITH SAID AIR-EVACUATING OPENINGIN COMMUNICATION WITH SAID AIREVACUATING MEMBER, EXHAUSTING AIR THROUGHSAID OPENING AND SAID AIR-EVACUATING PASSAGE AND THEREBY EVACUATING AIRFROM THE INTERIOR OF THE CONTAINER, APPLYING A HEATED SEALING MEMBERAGAINST THE OUTER SIDE OF SAID WALL AROUND THE AIR-EVACUATING MEMBERBEFORE TERMINATING THE EVACUATION OF AIR FROM THE CONTAINER, AND MOVINGTHE HEATED SEALING MEMBER AGAINST THE WALL TO PRESS THE WALL AGAINSTSAID PATCH TO SEAL SAID WALL AND PATCH TOGETHER AND CLOSE FLUIDCOMMUNICATION BETWEEN THE INTERIOR OF THE CONTAINER AND THE OPENINGTHROUGH THE AIR-EVACUATING PASSAGE.